1. Field of the Invention
The present invention relates to a multi-layered hose which is suitable for use as a filler hose for automobiles.
2. Description of the Related Art
Conventionally, a rubber material such as NBR.PVC rubber which shows oil resistance and oil penetration resistance is used as a filler hose (a fuel hose) for automobiles.
However, the above filler hose comprising only rubber can't cope with recent severe regulations of oil penetration resistance.
To solve the above problem, as shown in FIG. 25, a thin and fluorine-contained rubber inner layer 102 is formed at the inner periphery surface of a rubber outer layer 100.
The above hose having the fluorine-contained rubber inner layer 102 shows excellent efficiency, but the cost is high. So, it is not suitable for practical use.
Concerning the conventional hose for transmitting refrigerant, as shown in FIGS. 26 and 27, it is usual that a thin resin inner layer 104 is laminated on the inner periphery surface of a rubber outer layer 100.
When the above laminated structure is applied to a filler hose, the resin inner layer 104 having excellent oil resistance and excellent oil penetration resistance is laminated on the inner periphery surface of the rubber outer layer 100. Therefore, it is possible to easily obtain excellent oil resistance and excellent oil penetration resistance while maintaining flexibility which is required for the hose. Furthermore, it is possible to obtain an inexpensive hose.
In this case, a hard resin material is usually used as the resin inner layer 104, and the resin inner layer 104 is formed to have a certain thickness which is required for obtaining oil resistance and oil penetration resistance. This is because the hard resin material shows more excellent oil resistance than that of the soft resin material.
Concerning the conventional hose having the above laminated structure, as shown in FIG. 29, a resin tube (a resin inner layer 104) is extrusion-molded. Then, a rubber tube (a rubber outer layer 100) is extrusion-molded and laminated on the outside of the resin inner layer 104. Furthermore, the obtained rubber tube is valcanized or semi-valcanized, and bent to be in the certain direction. After that, the obtained rubber tube is valcanized to be produce the hose as shown in FIG. 28. The resin inner layer 104 in the inside of the obtained hose has the same thickness at either the hose main portion or the hose edge portion.
Concerning a filler hose, a mating pipe made of metal is inserted into the inside of the hose edge portion. Since a hard resin inner layer is formed in the inside of the hose edge portion to have a certain thickness, the mating pipe is not fully adhered to the inside of the hose edge portion, thereby not obtaining enough sealing.